The present invention relates to computer systems, and more specifically to disk subsystems in computer systems.
Mainframe disk subsystems are well known in the art. FIG. 1 illustrates a mainframe computer system with a conventional disk subsystem. The computer system 100 includes a disk subsystem 102 and a host 104. The disk subsystem 102 includes a disk array 106, a cache 108, and a processor 110 which controls the functioning of the disk subsystem 102. The host 104 comprises software specifically for communication with the disk subsystem 102, and does so by interfacing with the processor 110. One of the functions of the processor 110 is to provide statistics and other characteristics of the disk array 106 to the host 104. Examples of disk characteristics of interest to the host 104 include a table of ownership, the amount of space used on the disks 106, and performance characteristics. An important performance characteristic is disk utilization, which tells the host 104 how busy are each disk in the array 106. In a mainframe environment, as illustrated in FIG. 1, obtaining the disk utilization characteristic is well known in the art. However, a problem arises when the disk subsystem attempts to communicate with open system hosts, such as hosts which run UNIX, Windows NT, or some other type of open operating system. The parameters relevant to disk characteristics sent from the processor 110 to the host 104 is not in a format which is understandable by the open system host. Thus, in an open systems environment, the open system host is unable to obtain disk characteristics, including the disk utilization characteristic.
Accordingly, there exists a need for a method and system for providing parameters for a disk subsystem to an open system host. The method and system should be able to provide disk utilization which is understandable to the open system host. The present invention addresses such a need.
The present invention provides a method and system for reporting disk utilization in a computer system. The method includes collecting at least one parameter pertaining to a disk array in a disk subsystem by a processor in the disk subsystem; transferring the at least one parameter from the processor to an open system host; and calculating disk utilization based upon the at least one parameter. The method and system is able to provide disk utilization which is understandable to the open system host. In a preferred embodiment, the disk utilization is provided by collecting the relevant parameters from the microcode in the processor of the disk subsystem, and then calculating the average disk utilization per disk based upon the parameters. Thus, an open system host is able to obtain a useful characteristic for determining the performance of the disk subsystem.